Gruesome footage of a colossal spider draining the blood from the neck of a gecko has gone viral on the Internet.

The clip shows the huge creepy crawly with its fangs sunk deep into the neck of the lizard, which twitches and struggles even as the blood drips from its wound.

But the hapless prey is no match for the ravenous arachnid, which keeps its slowly dying meal tightly trapped beneath its forelegs and mandibles.

Uncomfortable viewing: A three-minute clip of a spider draining the blood from a lizard has gone viral

Unsettling: The massive huntsman spider had a tight hold of the lizard, which it had pumped full of venom

The unsettling three-minute clip was, judging by the voices that can be heard in the background, apparently filmed at night somewhere in Asia.

It was uploaded to the LiveLeak video hosting site a day ago and has since spread across news media, social networks and other video hosting sites, picking up millions of views.

An Australian commenter on LiveLeak identified the predator as a huntsman spider, so called because of their speed and mode of hunting.

'They look scary, but they actually don't bite, and will keep your home clear of insects, and, well, lizards I guess,' he wrote.

Not that dangerous: Huntsmen spider bites are generally not fatal to humans, and people even encourage them around their homes because they eat other pests like insects

Like most spiders, huntsmen use venom to immobilise their prey and help start digesting them before even swallowing a morsel.

So by the time this one got around to eating, the poor lizard was probably unable to fight back.

Their bites are generally not fatal to humans. They cause little more then localised swelling and pain, sometimes escalating to nausea, headache, vomiting, irregular pulse and heart palpitations, according to Wikipedia.